The present invention is directed to a pressure sensor within a vapor recovery system and, more particularly, to a pressure sensor mounted about a flow restrictor within a vapor recovery path.
A vapor recovery system captures vapors produced during a fueling operation. The system usually includes a vapor recovery path that extends between a nozzle, used for dispensing fuel, and a fuel storage tank. A vapor recovery pump, or other vacuum creating device, creates a vacuum within the path such that the vapor is pulled into the nozzle end, through the vapor recovery path, and into the underground storage tank. The system prevents the unwanted emissions of hydrocarbon and other potentially harmful gases that may be detrimental to the environment.
To ensure the system is effectively capturing vapors, it is necessary for sensors or other like monitoring equipment to be placed along the vapor recovery path. Governing bodies, such as the California Air Resources Board (CARB), set specific requirements for the amount of vapor captured and returned to the storage tank to comply with the U.S. Federal Clean Air Act Amendments of 1990.
However, many vapor recovery systems cannot recognize if vapor is actually being returned through the fuel dispenser to the underground storage tank. Failure of vapor being returned may be due to the occurrence of a pump failure or a leak along the vapor recovery path. Even though the vapor recovery system may be operational, such a failure or leak may not be detected by the system allowing vapors to escape into the atmosphere.
One manner of providing self-compliant vapor recovery systems is to provide technology to determine if a flow rate exits in the vapor return path when the vapor recovery system is operational. If flow rate does not exist in the vapor return path, vapors are not being recovered. This may be due to a malfunction in the vacuum creating device or a leak in the hose, but, nevertheless vapors are not being recovered as intended.
A vapor flow meter, such as that described in U.S. Pat. No. 5,860,457, entitled xe2x80x9cGasoline Vapor Recovery System and Method of Utilizing Vapor Detectionxe2x80x9d is one type of device that can be used to measure flow rate of vapor being returned in the vapor return path. However, a vapor flow meter is expensive, can be damaged by the presence of liquid or debris in the vapor stream, and is difficult to access and replace when damaged. The meter should meet certain safety requirements, such as those established by Underwriter""s Laboratories (hereinafter, U.L.), since the vapor may be at a flammable level.
Therefore, there exists a need to provide other devices that are less expensive and are easily connected to the vapor recovery return path that can measure flow rates in a vapor recovery return path.
The present invention is directed to a pressure sensor positioned along a vapor recovery path. In one embodiment, a flow restrictor is positioned along the vapor recovery path. The pressure sensor includes a first input and a second input, with each of the inputs being positioned about the flow restrictor to determine the pressure change.
The flow restrictor may have a variety of structures, including an orifice, laminar flow element, venturi, etc. Within the venturi, the inputs are positioned about the neck, narrowing sections, and vapor recovery path to sense the change in pressure.
Another embodiment of the invention features a vapor sensor positioned adjacent to the flow restrictor. The vapor sensor includes an inlet and an outlet extending from said vapor recovery path for directing vapor through a testing zone. The inlet and outlet of the vapor sensor, and the inputs of the pressure sensor are positioned about the flow restrictor for efficient operation.
The present invention is also directed to a pressure sensor that is mounted to the vapor recovery path. The vapor recovery path has an interior passage for containing vapors and an exterior mounting platform. An aperture extends between the interior passage and the mounting platform. The pressure sensor is mounted to the mounting platform and includes a pressure sensor controller and at least one input. The input includes a first end operatively connected to the pressure sensor controller and a second end sized to extend through the aperture into the interior passage.
In this embodiment, the pressure sensor controller may be mounted within a mounting device, also referred to as a xe2x80x9cmount.xe2x80x9d The mount may have a substantially flat surface that mates with a substantially flat surface of the mounting platform. Fasteners may provide for removably mounting the pressure sensor to the mounting platform.